Entropy generation study due to MHD double-diffusive convection in the rectangular cavity with built-in rectangular blockage

Abstract

In the present work, the influence of the aspect ratio of the rectangular cavity (length > width) and the built-in rectangular blockage (length > width) on the local and global entropy generation (EG) characteristics due to double-diffusive convection and external magnetic field have been explored. Particularly, the effect of the pertinent parameters, such as the aspect ratio of the cavity and blockage Lewis number Rayleigh number Hartmann number and buoyancy ratios on the EG characteristics have been explored. The working fluid is considered to be a liquid metal-sodium–potassium alloy (Pr = 0.054). Lattice Boltzmann method numerical scheme is employed to solve the double-diffusive natural convection phenomenon. The increase in Ra induces an enhancement in the localized EG terms, whereas the augmentation in Ha diminishes the local total EG (S Total) for a given Ra. The dominance of thermal and species transport irreversibility in the cavity was noticed for Conversely, for AR = 4, the significance of flow friction irreversibility within the cavity was observed (). The results of the work are also summarized in terms of simpler empirical correlations of and ST , which might be useful for possible engineering design purposes.